One dog was fatally stabbed and another injured when a Brentwood man attacked the family pets during a dispute that started at home with his girlfriend on Tuesday morning, Suffolk police said.

An order of protection was issued for four other dogs in the household against Malik Fields, 25, police said, but the order goes further.

"He cannot initiate any contact with any animals," said Det. Sgt. Jeffrey Walker of the Third Precinct. That includes going to the zoo and petting someone's dog, he said.

Fields had been arguing with his girlfriend in the hours before dawn at his Freeman Avenue residence, Walker said. When his sister tried to end the fighting, he threatened her with a pocket knife with about a 3-inch blade, he added.

The sister called police, and Fields stabbed two of the family's six pit bulls between 4-5 a.m., investigators said. He was arrested about 5:30 a.m., police said.

There was no indication the dogs were attacking Fields, so why he stabbed them and other details were not clear because the family has not fully cooperated in the investigation, authorities said.

Storm, a 1-year-old male pit bull, had a knife wound that was at least an inch deep in his rear end and an artery may have been cut, said Det. Jennifer Pape of the Suffolk County Society for Prevention of Cruelty to Animals. The family rushed him to the Veterinary Medical Center of Long Island in West Islip, where he was euthanized, authorities said.

But then Pape said she and police learned a second male pit bull named Chocolate had been found with a deep stab wound in the shoulder and they rushed back to the house. The family had reached out to Strong Island Rescue because they didn't have the funds for Chocolate's care, the SPCA detective said, and the group arranged for the pit bull's treatment at the Animal Medical Hospital of Centereach, where the dog, whose age was unknown, is recovering.